Jan 7th 2014, 20:54:33
As mentioned earlier, you should plan your risk vs rewards.
1. Don't spy, pure estimate based on countries near target's NW.
2. Spy target, then guess allied defenses. (Or send double to avoid failure)
3. Spy target, do an ally spy to determine who are the allies, and estimate their defenses based on the allies NW.
4. Spy target, do ally spy, and then spy those allies for exact break. For countries in GDI, you have to guesstimate based on NW, or past saved ops.
For techers, saving turns might be a risk worth taking, since spying means turns spent not teching for income. For non-techers it is less worth it because the benefit is either +1 CS or 20% cash income (not great for non-cashers), but you of course risk losing spies and lower your SPAL.